# File lib/phusion_passenger/utils/hosts_file_parser.rb, line 36
        def initialize(filename_or_io = "/etc/hosts")
                if filename_or_io.respond_to?(:readline)
                        read_and_parse(filename_or_io)
                else
                        File.open(filename_or_io, "rb") do |f|
                                read_and_parse(f)
                        end
                end
        end